SEATTLE — Defensive end Cliff Avril was released by the Seattle Seahawks on Friday with a failed physical designation due to a neck injury that cost him most of the 2017 season.

Avril's release was expected and could mean the end of a 10-year career during which he was a standout player for the Seahawks and the Detroit Lions.

Avril was injured in Week 4 last season while trying to chase down Indianapolis quarterback Jacoby Brissett. The back of Brissett's foot caught Avril in the chin as he lunged to make the tackle. Avril was seen shaking his arms and flexing his hands after the impact.

While the play looked innocuous, Avril's head snapped back violently and he suffered a neck injury. Avril never revealed the specific diagnosis for his injury but coach Pete Carroll repeatedly called it a serious situation. Avril had neck surgery following the season.

"Thank you 12s for making the last 5 years in Seattle so amazing!" Avril wrote in a post on Instagram . "Your cheers on Sundays are unmatched, and you guys are by far the best fans in the NFL! Most importantly, I appreciate and value the lifelong friendships I've made. You all have supported my family, my foundation (the Cliff Avril Family Foundation), and I throughout my entire tenure, and I could not have asked for more! THANK YOU to the entire Seahawk organization as well as my teammates. You all made me a Pro Bowler and a Super Bowl Champ! I am forever grateful."

Avril arrived in Seattle before the 2013 season and instantly helped transform the Seahawks defense into one of the best in recent memory. He was part of a rotation at first but became a full-time starter in 2014. His best season came in 2016 when Avril had a career-high 11½ sacks and was voted to the Pro Bowl for the only time in his career.

Avril spent five seasons in Detroit before coming to Seattle. He was a third-round pick out of Purdue and suffered through a 0-16 season in his rookie year with the Lions. He became a standout in Detroit but experienced his greatest team success in Seattle, helping the team win the Super Bowl in his first season with the Seahawks. He made a return trip to the championship game with the team the following year.

Releasing Avril will save Seattle about $6 million against the salary cap. But the Seahawks will also be faced with replacing another productive standout from a defense that had already seen the departure of Michael Bennett and Richard Sherman earlier this offseason.